The current trend in the semiconductor industry is to use dry etching techniques in the fabrication of electronic devices and structures. This is because conventional wet development utilizing solvents does not provide the anisotropic development which is necessary to achieve optimal dimensional control of microstructures. It follows that an anisotropic etch of a layer of material can take place only if the resist layer thereover is developed anisotropically. The most advantageous way of accomplishing this would be to dry develop the pattern in the resist, preferably in the same etching apparatus utilized to etch the underlying layer.
Reports of dry developable resists have only recently begun to appear in the literature. Resists developable by x-ray have been described which are both positive and negative working. To date, however, the only dry developable photoresists reported in the literature are negative acting. This is so regardless of whether the resists are organic or inorganic, such as silver sensitized antimony sulfide or germanium selenide. Because positive-working resists are preferred for the ultrafine dimensions of the microstructures, there exists a definite need for positive acting resist materials which are dry developable by, e.g. plasma etching. Such resists are provided in accordance with this invention.